The entire northbound lane of Greenwood Bridge has been removed and construction is under way to finish a retaining wall, said Chuck Lees, Caltrans resident engineer, last Thursday.

The soffit, or bottom part of the roadway on the bridge, is being poured. Once that is finished, the deck, which is where vehicles drive, will begin.

Lees estimates that the northbound lane will be complete and traffic rerouted onto it by the end of summer at the latest.

He expects the progress to speed up as the drier late spring and summer season begins.

One of the challenges they faced, aside from rain, is migratory bird season. The crew has to take special care, under the Migratory Bird Act, to not impact the purple martin population, while also not allowing them to nest in the soon-to-be demolished southbound lane.

Lees said a purple martin fledgling fell out of a nest and onto the site last year. Using a man lift, they were able to replace it in the nest.

He added that the little bird survived and flew off with the others by the end of the season.

The project, although slightly behind, is still expected to be completed by the end of summer 2014.